The present invention relates to a reagent for detecting cancer cells or diagnosing cancers, and a cell death-inducing agent.
Telomerase activity is often enhanced in malignantly transformed cells or immortalized cell strains, whereas telomerase activity is hardly detected in normal somatic cells excluding such as germ line cells, blood lineage cells and epithelial cells. Therefore, attempts to detect cancer using telomerase activity as an indicator have been made (Shay J W, Zou Y, Hiyama E, Wright W E. Telomerase and Cancer. Hum Mol Genet 10 (7): 677-85, 2001).
On the other hand, detection of cancer tissues and metastatic lymph nodes in vivo has been studied eagerly in the field of diagnostic imaging. For example, biological diagnosis with PET and image analysis fully utilizing neural network have been reported. Further, investigations into the anti-tumor activity and safety of replication-selective viruses have been reported (DeWeese T L, van der Poel H, Li S, Mikhak B, Drew R, Goemann M, Hamper U, DeJong R, Detorie N, Rodriguez R, Haulk T, DeMarzo A M, Piantadosi S, Yu D C, Chen Y, Henderson D R, Carducci M A, Nelson W G, Simons J W. A phase I trial of CV706, “A replication-competent, PSA selective oncolytic adenovirus, for the treatment of locally recurrent prostate cancer following radiation therapy”, Cancer Res 61(20):7464-72, 2001). The present inventors have also found that infecting cancer cells with a virus having a telomerase promoter and replication ability can kill the cancer cells by viral replication (Kawashima T, Kagawa S, Kobayashi N, Shirakiya Y, Umeoka T, Teraishi F, Taki M, Kyo S, Tanaka N, and Fujiwara T., Related Articles, Links Abstract “Telomerase-specific replication-selective virotherapy for human cancer”, Clin Cancer Res 10(1):285-92, 2004).
However, in situ cancer detection system during surgical operation has not yet been developed because of the difficulty in targeting cancer cells. Further, no research has been known to date in which the living body is infected with a virus and the viral kinetics within cancer cells is actually applied to visualization of cancer tissues.